Bonding Structure Manufacturing Method, Heating And Melting Treatment Method, And System Therefor

ABSTRACT

A soldering method capable of alleviating positional displacement between substrates even though a step of removing flux can be omitted is provided. 
     A temporary bonding agent  55  is applied onto multiple substrates  50   a   , 50   b , and a heater  33  heats the substrates while the substrates are temporarily bonded with the temporary bonding agent  55  interposed therebetween, and before the solder  54  is melted or while the solder  54  is melted, the temporary bonding agent  55  is evaporated, and the substrates  50   a   , 50   b  are bonded with solder with the melted solder  54  interposed therebetween.

TECHNICAL FIELD

The present invention relates to a bonding structure manufacturingmethod, a heating and melting treatment method, and a system thereforfor bonding multiple bonded members with a heat-melting material such assolder and eutectic-bonding insert metal interposed therebetween.

BACKGROUND ART

Techniques for manufacturing a bonding structure by bonding multiplebonded members with solder or bonding multiple bonded members witheutectic-bonding, with solder such as solder bumps or solder sheet or aeutectic-bonding insert metal interposed therebetween are widely used insemiconductor implementation steps. For example, in a semiconductorimplementation step, a technique for bonding an organic substrate and asemiconductor substrate with solder with solder bumps interposedtherebetween and a technique for bonding a semiconductor substrate and asemiconductor chip with solder with solder bumps interposed therebetweenare employed.

For example, when semiconductor substrates (semiconductor chips) arebonded with solder, it is necessary to remove an oxide film on thesurface of the solder bump in order to melt the solder bump and bondmultiple substrates with solder. In order to do this, multiplesubstrates are stacked and heated while a rosin-based reducing organicagent, which is called “flux”, is applied to the surface of thesubstrate. As a result, preferable solder bonding is made while theoxide film on the surface of the solder bump is reduced and removed bythe flux. After the solder bonding is made, the flux is removed bycleaning treatment such as solution cleaning and ion etching.

However, in recent years, the decrease in the size of the solder bumpstructure makes it difficult to remove the flux. In particular, when thepitch interval between adjacent solder bumps or the diameter of thesolder bump becomes several dozens of μm or less, it is difficult tosufficiently remove the flux. The flux that could not be removed makesflux residue. Due to the effect of chlorine included in the flux, theflux residue may cause insulation failure, which is called migration,between adjacent electrode structures (solder bumps). In a step offinally filling an underfill resin between substrates, the flux residuemakes it impossible to sufficiently fill the underfill resin, whichmakes clearance that is called void.

On the other hand, a method for omitting cleaning treatment usingflux-less solder bonding (cleaning-less method) is actually used as amethod for eliminating the effect of the flux residue. Morespecifically, carboxylic acid vapor such as formic acid is introducedinto a chamber, and the oxide film on the surface of the solder bump isreduced by this carboxylic acid, so that this makes it possible to makesolder bonding without using any flux (Cited documents 1, 2).

However, flux-less solder bonding raises a new problem in that it islikely to cause positional displacement between substrates. Morespecifically, as described above, when the flux is used, retaining force(stack force) occurs due to the flux residing between the multiplesubstrates, and this retaining force prevents the positionaldisplacement of the substrates from one another. In contrast, with theflux-less solder bonding, there is no flux between the substrates, andthe retaining force (stack force) cannot be given between thesubstrates. For this reason, in the cleaning-less method based on theflux-less solder bonding, it is likely to cause positional displacementbetween substrates, and this imposes limitation on cases where thecleaning-less method can be applied. In particular, when the substratesare bonded with solder with the solder bumps on the substrates, apositioning accuracy may be required to be about 1 to 2 μm, andtherefore, it is difficult to apply the cleaning-less method, which islikely to cause positional displacement. Similar problems may occur witheutectic-bonding.

Further, the positional displacement causes the problem not only whenthe substrates are bonded but also when a solder material is fixed ontoa substrate and solder bumps are formed, for example.

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Patent Application Laid-Open No.    11-233934-   Patent Literature 2: Japanese Patent Application Laid-Open No.    2001-244618

SUMMARY OF INVENTION Technical Problem

The present invention is to solve the problem concerning theconventional techniques as described above. More specifically, thepresent invention is to provide a bonding structure manufacturing methodand a manufacturing system capable of alleviating the positionaldisplacement between multiple bonded members even though cleaningtreatment can be omitted when a bonding structure is manufactured bybonding multiple bonded members with each other with a heat-meltingmaterial interposed therebetween.

In addition, the present invention is to provide a heating and meltingtreatment apparatus and a heating and melting treatment system capableof alleviating positional displacement in formation of solder when asolder material is subjected to heating and melting treatment and solderformation such as a solder bump is made.

Solution to Problem

(1) A bonding structure manufacturing method for manufacturing a bondingstructure by bonding a plurality of bonded members with a heat-meltingmaterial interposed therebetween includes: a step of preparing thebonded members with the heat-melting material being formed on at leastone of the plurality of bonded members; a temporary bonding step forapplying an organic agent onto surfaces of the plurality of bondedmembers facing each other, thereby temporarily bonding the plurality ofbonded members with the organic agent interposed therebetween; a bondingstep for melting the heat-melting material, thereby bonding theplurality of bonded members with the heat-melting material interposedtherebetween; and an evaporation step for evaporating the organic agentby heat application before or after the bonding step.

(2) A bonding structure manufacturing system for manufacturing a bondingstructure by bonding a plurality of members with a heat-melting materialinterposed therebetween includes: an application unit for applying atemporary bonding agent, which is a non-reducing organic agent, onto thebonded members with the heat-melting material being formed on at leastone of the plurality of bonded members; a heating unit for heating theplurality of bonded members temporarily bonded while the plurality ofbonded members are stacked with the temporary bonding agent interposedtherebetween; and a providing unit for providing carboxylic acid vaporto the plurality of bonded members, wherein before the heat-meltingmaterial is melted or while the heat-melting material is melted, theheating unit evaporates the temporary bonding agent, and on the otherhand, the heating unit heats the bonded members so as to bond the bondedmembers without flux in an atmosphere including the carboxylic acidvapor.

(3) A heating and melting treatment method for forming a solder byheating a member with a solder material attached and performing heatingand melting treatment on the solder material includes: a temporarybonding step for attaching the solder material onto the member, applyingan organic agent onto a surface of the member, and temporarily bondingthe solder material with the organic agent interposed therebetween; anevaporation step for evaporating the organic agent before the soldermaterial is melted or while the solder material is melted; and a formingstep for forming a solder by melting the solder material.

(4) A heating and melting treatment system for forming a solder byheating a member with a solder material attached and performing heatingand melting treatment on the solder material includes: an applicationunit for applying the solder material onto the member, and applying anorganic agent onto a surface of the member in order to temporarily bondthe solder material; a heating unit for heating the member with thesolder material temporarily bonded with the temporary bonding agentinterposed therebetween; and a providing unit for providing carboxylicacid vapor to the member, wherein before the solder material is meltedor while the solder material is melted, the heating unit evaporates thetemporary bonding agent, and on the other hand, the heating unit heatsthe member so as to form a solder without flux in an atmosphereincluding the carboxylic acid vapor.

Advantageous Effects of Invention

According to the present invention, when a bonding structure ismanufactured by bonding multiple bonded members with each other withsolder, the positional displacement between multiple bonded members canbe alleviated even though the cleaning treatment can be omitted. Whenthe solder is formed, the positional displacement of the solder materialcan be alleviated.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic configuration diagram illustrating a bondingstructure manufacturing system according to a first embodiment of thepresent invention.

FIG. 2 is a diagram illustrating an example of a substrate used in abonding structure manufacturing method according to the first embodimentof the present invention.

FIG. 3 is a diagram illustrating a first example of a substratedifferent from FIG. 2.

FIG. 4 is a diagram illustrating a second example of a substratedifferent from FIG. 2.

FIG. 5 is a diagram illustrating a subsequent step for the substrate ofFIG. 2 according to the first embodiment of the present invention.

FIG. 6 is a diagram illustrating a step subsequent to FIG. 5 accordingto the first embodiment of the present invention.

FIG. 7 is a diagram illustrating a temperature condition and a vacuumdegree condition according to the first embodiment of the presentinvention.

FIG. 8 is a diagram illustrating a step subsequent to FIG. 6 accordingto the first embodiment of the present invention.

FIG. 9 is a diagram illustrating a step subsequent to FIG. 8 accordingto the first embodiment of the present invention.

FIG. 10 is a diagram illustrating a step subsequent to FIG. 9 accordingto the first embodiment of the present invention.

FIGS. 11( a) and 11(b) are diagrams illustrating an example ofapplication of a temporary bonding agent according to a secondembodiment of the present invention.

FIG. 12 is a diagram illustrating heating and melting treatmentaccording to a fourth embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be hereinafter explained withreference to the appended drawings. In the explanation about thedrawings, the same elements are denoted with the same referencenumerals, and repeated explanation thereabout is omitted. The ratios ofthe sizes in the drawings are exaggerated for the sake of explanation,and may be different from the actual ratios.

A bonding structure manufacturing technique of the present inventionrelates to a technique for manufacturing a bonding structure by bonding(in particular, solder bonding or eutectic-bonding) multiple bondedmembers with a heat-melting member (such as solder or insert metal)interposed therebetween.

First Embodiment

A bonding structure manufacturing technique of the first embodiment ofthe present invention relates to a technique for manufacturing a bondingstructure by bonding multiple bonded members with solder or bondingmultiple bonded members with eutectic-bonding. This bonding structuremanufacturing technique can also be used for mechanical solder bonding,but preferably, the bonding structure manufacturing technique is atechnique for bonding substrates with each other, bonding chips witheach other, or bonding a substrate and a chip, with solder bonding, andis to electrically connect electrode structures of a pair of substrateswith each other, electrically connect electrode structures of chips witheach other, and electrically connect an electrode structure of asubstrate and an electrode structure of a chip, with solder bonding.

It should be noted that the substrate may be an organic substrate suchas a print substrate, and may be semiconductor substrate and adielectric substrate such as a silicon substrate or a compoundsemiconductor substrate. The chip may be a semiconductor chip or adielectric chip. Hereinafter, an example of a case where semiconductorsubstrates are bonded with each other with solder bumps interposedtherebetween will be explained.

The bonding structure manufacturing technique according to the presentembodiment includes forming electrode structures including solder bumpsor the like on multiple semiconductor substrates, applying an organicagent onto the semiconductor substrates, and temporarily bonding thesubstrates with this organic agent. Then, within a chamber, this organicagent is evaporated before the solder is melted or while the solder ismelted, so that the organic agent is made into a solder bonding.

In particular, in the present embodiment, although the cleaning-lessmethod based on the flux-less solder bonding is employed to reduce anoxide film of solder by introducing carboxylic acid into the chamber,non-flux organic agent, i.e., a temporary bonding agent which is anon-reducing organic agent, is applied to the substrates and thesubstrates are temporarily bonded before the substrates are placed intothe chamber. As described above, instead of using the flux, a dedicatedtemporary bonding agent for giving retaining force (stack force) betweenthe substrates is used to prevent positional displacement of thesubstrates, and meanwhile, before the reducing treatment of the oxidefilm with the carboxylic acid, or at the same time as the reducingtreatment, the temporary bonding agent is evaporated, and thereafter thesubstrates are bonded with each other.

According to the above configuration, the present invention alleviatespositional displacement between multiple bonded members even though thecleaning treatment can be omitted.

FIG. 1 is a diagram illustrating a schematic configuration of a bondingstructure manufacturing system according to the present embodiment.

A bonding structure manufacturing system 1 is a substrate solderingsystem for bonding substrates with each other. When roughly divided, themanufacturing system 1 mainly includes a temporary bonding apparatus 20and a solder melting apparatus 30.

The temporary bonding apparatus 20 includes a dispenser 21 and analignment mechanism 22. The dispenser 21 is an application unit forapplying a temporary bonding agent, which is a non-reducing organicagent, onto a substrate surface formed with solder such as solder bumps.When the organic agent is applied, the organic agent can be applied onthe entire surface of the substrate in a planar manner, or may beapplied dispersedly in spots manner. In the present embodiment, however,the organic agent is applied in a planar manner. The alignment mechanism22 is positioning means for positioning electrode structures ofsubstrates so as to cause the multiple substrates to face each other tosandwich the applied temporary bonding agent, and temporarily bondingthe substrates. The temporary bonding apparatus 20 is the same as anapparatus called a flip chip bonder, except that the applied organicagent is not a flux agent, and therefore, the temporary bondingapparatus 20 will not be explained in detail.

On the other hand, the solder melting apparatus 30 includes a chamber31, a carboxylic acid providing unit 32, and a heater 33 within thechamber 31. Substrates that have been temporarily bonded by thetemporary bonding apparatus 20 are conveyed into the chamber 31. Theproviding unit 32 provides carboxylic acid vapor into the chamber 31with predetermined timing. However, in some cases, the treatment can bemade not in the chamber 31 but in an open environment.

The providing unit 32 includes a carboxylic acid vapor providing system34 and a valve 35 that is opened and closed with predetermined timing.The providing system 34 mixes carrier gas such as reducing gas such ashydrogen or carbon monoxide or non-oxidizing gas such as nitrogen withcarboxylic acid vapor, and introduces the carrier gas mixed with thecarboxylic acid vapor into the chamber 31. For example, the providingsystem 34 includes a sealed container 36 containing carboxylic acidliquid and a carrier gas providing tube 38 providing the carrier gas viaa valve 37. The carrier gas providing tube 38 generates bubbles in thesealed container 36 (bubbling). However, the providing unit 32 may beanything as long as it can provide the carboxylic acid into the chamber31, and it may have a different configuration from the presentembodiment.

The heater 33 will be explained. The heater 33 is a heating unitprovided in the chamber 31. Before the solder is melted or while thesolder is melted, the heater 33 evaporates the temporary bonding agentas well as performs heating treatment in an atmosphere including thecarboxylic acid vapor, and heats substrates, which are bonded members,in order to achieve flux-less solder bonding. In particular, before thereducing treatment of the oxide film of the solder with the carboxylicacid or at the same time with the reducing treatment, the heater 33evaporates the temporary bonding agent. In order to prevent positionaldisplacement of the substrates, it is preferable not to evaporate allthe temporary bonding agents before the solder is melted, but when toomuch temporary bonding agent remains, the surface of the solder cannotbe exposed to the carboxylic acid vapor, which makes it difficult toperform the reducing treatment of the oxide film. Therefore, in terms ofthe reducing treatment, it is desirable to evaporate the temporarybonding agent before the solder is melted.

Further, the solder melting apparatus 30 includes a discharge pump 39for discharge and a carboxylic acid collecting unit (collectingmechanism) 40 attached or provided at the intake side or the dischargeside of the discharge pump 39 so as to collect the vaporized carboxylicacid. The carboxylic acid collecting unit 40 may be a filter attached tothe intake side or the discharge side of the discharge pump 39, or maybe a scrubber attached to the discharge side. The solder meltingapparatus 30 is connected via a valve 42 to a nitrogen providing tube 41for replacing (purging) the inside with nitrogen atmosphere.

In the solder melting apparatus 30 having the configuration as describedabove, the substrates temporarily bonded with temporary bonding agentare conveyed into the chamber. Before the solder is melted, inparticular, before the reducing treatment of the oxide film of thesolder with the carboxylic acid or at the same time with the reducingtreatment, the providing unit 32 provides the carboxylic acid vapor andthe heater 33 applies heat in accordance with the type of the temporarybonding agent in order to evaporate the temporary bonding agent. Exceptthese features, the detailed configuration is the same as theconfiguration of a generally-available solder melting apparatus, anddetailed description thereabout is omitted.

A conveying robot may be provided to pass substrates between thetemporary bonding apparatus 20 and the solder melting apparatus 30.

Subsequently, a bonding structure manufacturing method using the bondingstructure manufacturing system according to the present embodiment,i.e., a soldering method, will be explained.

First, as shown in FIG. 2, substrates 50 a, 50 b having solder bumpsformed on the surface thereof (hereinafter collectively referred to assubstrates 50) are prepared. In this case, the substrate 50 is asemiconductor substrate. The substrate 50 includes a semiconductorsubstrate main body 51 and an electrode structure on the substrate mainbody 51. More specifically, a copper post 52, a barrier layer 53 on thecopper post 52, and a solder bump 54 formed on the barrier layer 53 areprovided on the semiconductor substrate main body 51. The copper post 52is a first protruding portion made of copper (Cu) or copper alloy. Thebarrier layer 53 is an under barrier metal for preventing soldercomponent from diffusing into the copper post 52 when the solder bump 54is melted. For example, the barrier layer 53 is a Ni/Pd/Au stacked layerin which nickel (Ni), palladium (Pd), and gold (Au) are stacked in thisorder from the substrate main body 51. In the case of FIG. 2, the copperpost 52 (first protruding portion) is provided as the electrode portion,but the electrode portion is not limited to a protruding form. Moreover,the material thereof is not limited to copper or copper alloy.

The solder bump 54 is formed with lead-free solder such as Sn—Ag(tin-silver) solder that does not include any lead (Pb), lead-includingsolder such as Pb—Sn solder, or other solder. The formation of thesolder bump 54 itself is the same as conventional techniques for formingthe solder bump 54 with plating, and therefore, detailed descriptionthereabout is omitted. Unlike the present embodiment, it may be possibleto use an insert metal for eutectic-bonding instead of the solder bump54. In this case, the eutectic-bonding is made such that two types ofmaterials or more are diffused into each other to cause materialmovement at a treatment temperature and alloy reaction is made, so thatthe bonding is completed. This is a type of liquid phase diffusionbonding in which an insert metal and the like is temporarily melted anddissolved between surfaces to be bonded and thereafter they are bondedby isothermal solidification using diffusion, and is a bonding methodusing eutectic reaction on liquefaction.

Both of the pair of prepared semiconductor substrates 50 may beconfigured as shown in FIG. 2, but the configuration is not limitedthereto. For example, the substrate 50 a, which is one of thesubstrates, may be configured to be a substrate including a firstelectrode portion (for example, copper post) 52, the barrier layer 53,and the solder bump 54, and on the other hand, the substrate 50 b, whichis the other of the substrates, may be configured to be a substratewithout the solder bump 54 as shown in FIGS. 3 and 4 (FIG. 3). Thesolder bump 54 and the barrier layer 53 may be omitted from thesubstrate 50 b, which is the other of the substrates (FIG. 4). Inparticular, when both of the solder bump 54 and the barrier layer 53 areomitted from the substrate 50 b, which is the other of the substrates,and solder bonding is directly made with the second electrode portion(copper post 52), the substrates can be manufactured with less burden.In the present embodiment, the reducing treatment can be donesufficiently with the carboxylic acid, and therefore, even when thebarrier layer and the solder bump are omitted from the substrate 50 b,which is the other of the substrates, solder bonding can be directlymade with the second electrode portion

It should be noted that the bonding structure manufacturing techniqueaccording to the present embodiment is preferably used for the substrate50 provided with multiple solder bumps of which diameter is 100 μm orless while the pitch interval between adjacent solder bumps is 150 μm orless. However, the substrate 50 is not limited to this case.

Subsequently, as shown in FIG. 5, a temporary bonding agent 55 isapplied onto the substrate 50. The temporary bonding agent 55 is appliedonto the surfaces of the multiple substrates 50 a, 50 b facing eachother (hereinafter referred to as “bonded surfaces”). The bonded surfacecorresponds to a surface at a side where an electrode structure such asthe solder bump 54 is formed. The temporary bonding agent may be appliedto the bonded surfaces of both of the multiple substrates 50 a, 50 b.Alternatively, the temporary bonding agent may be applied to only thebonded surface of the substrate 50 a, which is only one of thesubstrates. Even when the temporary bonding agent is applied to only thebonded surface of the substrate 50 a, which is only one of thesubstrates, the temporary bonding agent is interposed between the pairof substrates 50 a, 50 b with the substrate 50 a being coming intocontact with the substrate 50 b, which is the other of the substrates,so that retaining force (stack force) can be given between thesubstrates 50 a, 50 b.

In the present embodiment, the temporary bonding agent 55 is applied ina planar manner onto the substrate 50 which is the bonded member. Whenthe temporary bonding agent 55 is applied uniformly in a planar manneras described above, the retaining force (stack force) increases. In thepresent embodiment, the temporary bonding agent 55 is a non-flux organicagent, i.e., non-reducing organic agent. In other words, in the presentembodiment, although the flux-less solder bonding is made, the temporarybonding agent 55 for giving retaining force (stack force) between thesubstrates is applied, instead of the flux, onto the bonded surfaces ofthe substrates 50. The reason why the non-reducing organic agent isdesirable is because, even if residue of the organic agent remains,insulation failure called migration can be prevented from occurring.More specifically, the temporary bonding agent 55 is desirably an agentthat does not include a component such as chlorine that adverselyaffects the substrate.

The temporary bonding agent 55 may include organic agent and viscositymodifier (thinning liquid). This is to adjust the viscosity. Theviscosity of the temporary bonding agent 55 is preferably within a rangeof 100 to 100000 (30 degrees Celsius mPa·S). More preferably, theviscosity of the temporary bonding agent 55 is within a range of 1600 to66000 (30 degrees Celsius mPa·S). This is because, when the viscosity istoo high, it becomes difficult to apply the agent, and on the otherhand, when the viscosity is too low, the retaining force (stack force)between the substrates is low, which does not provide sufficienttemporary bonding effect.

As explained later, the temporary bonding agent 55 is selected from amaterial that evaporates before the solder bump 54 is melted (beforereaching the melting point of the solder), when the substrates 50 areheated in the chamber 31. In particular, the temporary bonding agent 55is selected from a material that evaporates before the reducingtreatment of the oxide film of the solder with the carboxylic acid vaporor in parallel with the reducing treatment. More specifically, theboiling point of the temporary bonding agent 55 is set on the basis ofthe pressure in the chamber 31 before the reducing treatment of theoxide film of the solder and during the reducing treatment and thesubstrate temperature during the reducing treatment. When the pressurein the chamber 31 is considered, the pressure in the chamber 31 ispreferably a pressure of 1×10² to 1×10⁵ Pa before the reducing treatmentor during the reducing treatment in the present embodiment. The reasonwhy this range is preferable is because, when the pressure is less than1×10² Pa, for example, the substrates may be displaced due to bumping ofthe temporary bonding agent 55, and when the pressure is 1×10⁵ Pa ormore, it is the atmospheric pressure or more. When the range of thesubstrate temperature is considered, the substrate temperature rangeduring the reducing treatment is desirably 100 degrees Celsius to 350degrees Celsius. The reason why this kind of temperature range ispreferable is because formic acid such as carboxylic acid used for thereducing treatment begins to dissolve at about 350 degrees Celsius, andaccordingly, it is desirably 350 degrees Celsius or less, and on theother hand, depending on the type of the solder, reducing treatment maybe done at about 100 degrees Celsius with the carboxylic acid vapor.When the pressure range and the substrate temperature range as describedabove are considered, the temporary bonding agent 55 desirably has aboiling point of 100 degrees Celsius to 350 degrees Celsius at apressure of 1×10² to 1×10⁵ Pa. In general, depending on the type of thematerial of the solder, it is possible to use a different type oforganic agent that evaporates before the reducing treatment or duringthe reducing treatment (in general, before the solder is melted or whilethe solder is melted). More specifically, Pb-5Sb solder has a meltingpoint of 314 degrees Celsius, and the solder bonding temperature isabout 330 degrees Celsius to about 350 degrees Celsius. Sn-3.5Ag solderhas a melting point of 221 degrees Celsius, and the solder bondingtemperature is about 230 degrees Celsius to about 250 degrees Celsius.Some solders have melting points lower than that of Sn-3.5Ag solder.Therefore, the temporary bonding agent 55 may be selected depending onthe type of the material of the solder.

More specifically, according to the result of experiment, the temporarybonding agent 55 desirably includes at least one non-reducing organicagent selected from isobornyl cyclohexanol, terpineol, and propyleneglycol phenyl ether. The isobornyl cyclohexanol (MTPH) has a boilingpoint of 308 degrees Celsius (5%) 313 degrees Celsius (15%) with theviscosity of 65500 (30 degrees Celsius mPa·S). The terpineol (genericname: pine oil component includes 97% or higher terpin alcohols such asalpha-terpineol, beta-terpineol, and gamma-terpineol, which are isomers,which are the main components) has a viscosity lower than that of theisobornyl cyclohexanol (MTPH), and has a boiling point of 213 to 223degrees Celsius. The propylene glycol phenyl ether has a viscosity of22.7 (25 degrees Celsius mPa·S), and has a boiling point of 243 degreesCelsius (760 mmHg). In particular, in a case of Sn—Ag, the isobornylcyclohexanol (MTPH) is preferable.

The viscosity modifier may be appropriately selected from those of whichviscosities are less those of isobornyl cyclohexanol, terpineol, andpropylene glycol phenyl ether. For example, 2,4-diethyl-1,5-pentanediol(C₉H₂₀O₂) may be used as the viscosity modifier. The ratio of viscositymodifier added to the undiluted solution of the organic material may beselected appropriately, but it may be 0 to 90 weight percent.

It should be noted that the temporary bonding agent 55 may includemultiple types of non-reducing organic agents having different boilingpoints from each other. In this case, at least some of temporary bondingagent components evaporate earlier than other temporary bonding agentcomponents, so that, in a portion where the evaporated temporary bondingagent components existed, the surfaces of the solder bumps are exposedearlier, and the reducing treatment is started, whereby the solderbonding is made earlier. On the other hand, all the temporary bondingagents do not evaporate at a time, and therefore, over a relatively widetemperature range, the temporary bonding effect can be maintained, sothat this enhances the effect of preventing the positional displacement.For example, some of the temporary bonding agent components evaporatebefore the solder is melted, and the other temporary bonding agentcomponents evaporate while the solder is melted, but an agent obtainedby mixing these components can be used as the temporary bonding agent55.

Subsequently, after the temporary bonding agent 55 is applied, thealignment mechanism 22 positions the substrates 50 a, 50 b with respectto each other by causing the multiple substrates 50 a, 50 b to face eachother to sandwich the temporary bonding agent 55, so that the substrates50 a, 50 b are positioned opposite to each other. As a result, thetemporary bonding agent 55 gives the retaining force (stack force)between the substrates 50 a, 50 b, and the substrates 50 a, 50 b aretemporarily bonded to each other.

Subsequently, as shown in FIG. 6, the temporarily bonded substrates 50a, 50 b are conveyed into the chamber 31. In the chamber 31, thesubstrates 50 a, 50 b are arranged on the heater 33 with, for example, atray (not shown) interposed therebetween. In FIG. 6, the pair ofsubstrates 50 a, 50 b are shown, but, for example, multiple pairs ofsubstrates, multiple pairs of chips, and multiple sets of substrates andchips may be conveyed as bonded members at a time.

Subsequently, process is performed under temperature condition andvacuum degree condition as shown in FIG. 7. First, as shown in FIG. 7,using the pump 39, the chamber 31 is evacuated to about, for example, 10to 50 Pa. The degree of evacuation is not limited to about 10 to 50 Pa,and may be adjusted as necessary. Then, subsequent to the evacuationprocessing, or in parallel with the evacuation processing, thesubstrates 50 a, 50 b are heated with the heater 33, and the substratetemperature is increased.

Subsequently, the carboxylic acid vapor is introduced into the chamber31. By providing the carboxylic acid vapor, the chamber 31 is at about100 to 10000 Pa. The carboxylic acid vapor is desirably introduced atleast before the temperature of the substrates 50 a, 50 b reaches themelting point of the solder. For example, when the solder is Sn-3.5Ag(melting point of 221 degrees Celsius), it is heated to about 230degrees Celsius to 250 degrees Celsius suitable for soldering, but atabout 200 degrees Celsius or higher, the reducing effect of thecarboxylic acid is enhanced, and the reducing treatment is started. In acase of Pb-5Sn (melting point of 314 degrees Celsius), it is heated toabout 330 degrees Celsius to 350 degrees Celsius suitable for soldering,but at about 250 degrees Celsius or higher, the reducing effect of thecarboxylic acid is enhanced, and the reducing treatment is started.

Then, in the present embodiment, before the reducing treatment of theoxide film of the solder with the carboxylic acid vapor or in parallelwith the reducing treatment, the temporary bonding agent 55 isevaporated. More specifically, when the solder is Sn-3.5Ag, the reducingtreatment is performed at around 200 degrees Celsius, e.g., about 180degrees Celsius to 250 degrees Celsius, and the solder bonding is madeat about 230 degrees Celsius to 250 degrees Celsius, but before thisreducing treatment or in parallel with the reducing treatment, thetemporary bonding agent 55 is evaporated. Likewise, when the solder isPb-5Sn, the reducing treatment is performed at around 250 degreesCelsius, e.g., about 220 degrees Celsius to 350 degrees Celsius, and thesolder bonding is made at about 330 degrees Celsius to 350 degreesCelsius, but before this reducing treatment or in parallel with thereducing treatment, the temporary bonding agent 55 is evaporated. Evenwhen the solder is made of other materials, before the reducingtreatment of the oxide film of the solder with the carboxylic acid vaporor in parallel with the reducing treatment, the temporary bonding agent55 is evaporated. As shown in FIG. 7, when the evacuation to about 10 to50 Pa makes it easy to evaporate the temporary bonding agent 55. Inother words, it is effective to temporarily enhance the vacuum degree inthe chamber 31 so that the temporary bonding agent 55 easily evaporates.

As shown in FIG. 8, as the temporary bonding agent 55 graduallyevaporates, the solder bump 54 is gradually exposed to the carboxylicacid vapor. As a result, the oxide film on the surface of the solderbump 54 is reduced.

At this occasion, the temporary bonding agent 55 may include multipletypes of non-reducing organic agents having different boiling pointsfrom each other. In this case, at least some of temporary bonding agentcomponents evaporate earlier than other temporary bonding agentcomponents. In a portion where the temporary bonding agent componentsthat evaporated earlier existed, the reducing treatment is startedearlier, and on the other hand, all the temporary bonding agentcomponents do not evaporate at a time due to the difference of theboiling points, and therefore, the temporary bonding effect can bemaintained over a relatively wide temperature range.

Then, as shown in FIG. 9, the flux-less solder bonding is made. Beforethe solder bump 54 is melted, a portion or all of the temporary bondingagent 55 may be evaporated, or while the solder bump 54 is melted, thetemporary bonding agent 55 may be evaporated. In terms of preventing thepositional displacement, the temporary bonding agent 55 is desirablyevaporated after the solder bump 54 starts to melt. However, in terms ofsufficiently performing reducing treatment by earlier exposing thesurface of the solder bump 54 to cause the surface of the solder bump 54to come into contact with the carboxylic acid vapor, it is desirable toevaporate a portion or all of the temporary bonding agent before thesolder bump 54 is melted. More specifically, at least a portion of thetemporary bonding agent 55 is evaporated, and the solder bump 54 isexposed, and in this exposed portion, the oxide film is reduced andremoved. Even when the temporary bonding agent 55 is completelyevaporated before the solder bump 54 is melted, the solder bonding canbe made without any positional displacement. Then, when the temperatureof the substrates 50 a, 50 b is a solder bonding temperature (forexample, when the solder is Sn-3.5Ag, the solder bonding temperature isabout 230 degrees Celsius to 250 degrees Celsius), the solder in thatportion is melted and soldered (solder bonding). The temporary bondingagent 55 is completely evaporated, and then the solder bump 54 iscompletely exposed, and the reducing treatment is performed, so that thesolder bonding is completely made by sufficiently melting the solder. Atthis occasion, the soldering processing (reflow) is completed. If alarge positional displacement can be prevented with the temporarybonding agent 55, the positional displacement is thereafter corrected byself-alignment due to the effect of the surface tension of the solder.When the temporary bonding agent 55 is evaporated while the solder 54 ismelted, the temporary bonding effect can be maintained until thesoldering effect due to the melted solder 54 is caused. Even when thetemporary bonding agent 55 is evaporated before the solder 54 is melted,this reduces the time from when the temporary bonding agent 55 iscompletely evaporated and the temporary bonding effect is lost to whenthe soldering processing is completed, and therefore, the positionaldisplacement of the substrates 50 a, 50 b can be prevented oralleviated.

After the soldering processing (reflow), the substrate temperaturebegins to decrease, and the discharge pump 39 discharges the carboxylicacid vapor. The carboxylic acid collecting unit (collecting mechanism)40 collects vaporized carboxylic acid. Thereafter, the inside of thechamber 31 is replaced (purged) with gas such as nitrogen introducedfrom the nitrogen providing tube 41, and thereafter, the bondingstructure of which solder bondings have been completed, i.e., thesolder-bonded substrates 50, are retrieved.

Subsequently, as shown in FIG. 10, after the step of the solder bonding,the underfill resin 56 is filled between multiple substrates, i.e., thesubstrate 50 a and the substrate 50 b, for the retrieved substrates 50of which solder bondings have been made. This is to enhance the pastingstrength of the solder-bonded substrates 50 and to protect them. At thisoccasion, the organic agent (temporary bonding agent) between thesubstrate 50 a and 50 b have already been evaporated and removed.Therefore, unlike an ordinary solder bonding using flux, substantiallyno organic agent exists between the substrates 50 a and 50 b, and evenafter cleaning, no residue remains. As a result, in the step of fillingthe underfill resin between the substrates, generation of clearancescalled voids caused by insufficient filling of the underfill resin dueto the residue can be prevented. Even when the organic agent (temporarybonding agent) does not remain between the substrates and a small amountof temporary bonding agent remains, insulation failure called migrationcan be prevented because the temporary bonding agent is not rosinreducing organic agent but is non-reducing organic agent.

As illustrated in examples explained below, according to the techniqueof the present embodiment, when the substrates are bonded that areformed with solder bumps of which diameter is about several dozens of μmor of which pitch is about several dozens of μm, flux-less solderbonding can be made with a positional displacement of 2 μm or less.

The bonding structure manufacturing technique of the first embodiment ofthe present invention has been explained hereinabove, but the presentinvention is not limited to this case, and can be changed as necessary.

For example, the temperature condition and the vacuum degree conditionare not limited to what is shown in FIG. 7. For example, in order toreduce the process time, it is desired to monotonically increase thesubstrate temperature from the entry of the substrate to the reflow asshown in FIG. 7, but it is not limited thereto. For example, before thesubstrate temperature reaches the solder bonding temperature, thereducing treatment may be performed by maintaining the substratetemperature at a temperature lower than the solder bonding temperatureby about 50 to 80 degrees Celsius for a certain period of time.Alternatively, the temperature of the substrate may be controlled byconveying the substrates 50 a, 50 b onto the heater 33 or moving thesubstrates 50 a, 50 b out of the heater 33 while the temperature of theheater 33 is maintained at a certain level.

According to the present embodiment, the following effects can beobtained.

(1) The organic agent 55 evaporates before the solder 54 is melted orwhile the solder 54 is melted, and therefore, after the solder bondingis made, cleaning for removing the organic agent 55 is unnecessary.Therefore, the residue of the organic agent 55 does not remain, and inparticular, when the electrode structure of the substrate 50 a and theelectrode structure of the substrate 50 b are bonded with solder,migration and other contaminations do not occur. In addition, in thestep of filling the underfill resin into the gap, generation of voidscaused by insufficient filling of the underfill resin due to the residueof the organic material can be prevented.

(2) Since the residue of the organic agent 55 does not remain, this canbe used for, in particular, the solder bonding of the substrate havingthe solder bumps 54 of which diameter is about several dozens of μm orless and of which pitch between adjacent solder bumps is about severaldozens of μm, and for, in particular, the fine structure of several μmor less.

(3) In particular, the flux-less solder bonding is made using thetemporary bonding agent 55 which is non-reducing organic agent as theorganic agent. Therefore, even with the flux-less solder bonding, theretaining force (stack force) can be given to the substrates with thetemporary bonding agent 55, and the positional displacement can beprevented. Even if a small amount of temporary bonding agent remains,migration and other contaminations do not occur unlike the flux agent.

(4) In particular, before the reducing treatment of the oxide film ofthe solder 54 with the carboxylic acid vapor or in parallel with thereducing treatment, the temporary bonding agent is evaporated, andtherefore, as the temporary bonding agent 55 is gradually evaporated,the solder bump 54 is gradually exposed to the carboxylic acid vapor.Therefore, the temporary bonding agent 55 prevents the positionaldisplacement of the substrates 50 a, 50 b, whereas this does not blockthe reducing treatment with the carboxylic acid vapor. Even when thetemporary bonding agent 55 is completely evaporated before the solderbump 54 is melted, the solder bonding can be made without positionaldisplacement. More specifically, the positional displacement isprevented while the substrates are conveyed, and with the effect of thesurface tension of the solder due to the melted solder bump 54, thesubstrates are self-aligned, and the positional displacement iscorrected.

(5) The vacuum degree in the chamber 31 is temporarily enhanced so thatthe temporary bonding agent 55 easily evaporates, whereby the temporarybonding agent 55 sandwiched by the substrates 50 a, 50 b having finestructures (52, 53, 54) is likely to evaporate.

(6) The temporary bonding agent 55 has a boiling point of 100 degreesCelsius to 350 degrees Celsius at a pressure of 1×10² to 1×10⁵ Pa, andtherefore during the reducing treatment or immediately before thereducing treatment, the temporary bonding agent 55 remains to give theretaining force, and on the other hand, the reducing treatment is notblocked.

(7) The temporary bonding agent 55 is at least one non-reducing organicagent selected from isobornyl cyclohexanol, terpineol, and propyleneglycol phenyl ether, and therefore during the reducing treatment orimmediately before the reducing treatment, the temporary bonding agentremains to give the retaining force, and on the other hand, the reducingtreatment is not blocked. Materials causing migration and othercontaminations are not included. Further, the viscosity is appropriate,and a sufficient retaining force (stack force) can be given.

(8) When the temporary bonding agent 55 includes multiple types ofnon-reducing organic agents having different boiling points from eachother, at least some of temporary bonding agent components evaporateearlier than other temporary bonding agent components, so that, in aportion where the evaporated temporary bonding agent components existed,the reducing treatment can be started earlier. On the other hand, allthe temporary bonding agents do not evaporate at a time, and therefore,the temporary bonding effect can be maintained over a relatively widetemperature range, so that the effect of preventing the positionaldisplacement is enhanced.

(9) The temporary bonding agent 55 is diluted by the viscosity modifierso that the viscosity becomes 1×10² to 1×10⁵ mPa·s, and therefore, whilethis prevents a viscosity that is too high to make applicationimpossible, this can also prevent the viscosity from becoming too lowand prevent small retaining force of the substrates.

(10) In particular, this is useful for bonding substrates that arearranged with the solder bumps 54 having diameters of 100 μm or lesswhich are arranged while the pitch interval between adjacent bumps is150 μm or less.

(11) The present embodiment is of a type using the solder bumps 54, butthe oxide film can be reduced sufficiently with the carboxylic acidvapor, and therefore, one of the pair of the substrates 50 a, 50 b maynot have the barrier layer 53 and the solder bump 54, and may have onlya copper post (a second protruding portion made of copper) 52 formedthereon, so that solder bonding can be made directly. Accordingly, thesubstrates 50 b can be manufactured with less burden.

(12) In the present embodiment, the temporary bonding agent 55 isapplied in a planar manner onto the substrates 50, and therefore, theamount of temporary bonding agent 55 increases, and this increases theretaining force (stack force).

Second Embodiment

Subsequently, the second embodiment of the present invention will beexplained. In the first embodiment, a case where the temporary bondingagent is applied in a planar manner onto the substrates has beenexplained. However, in the second embodiment, the temporary bondingagent is applied in spots manner onto multiple positions. Except thisfeature, the bonding structure manufacturing technique of the presentembodiment is the same as the first embodiment. Accordingly, the samemembers as the members of the first embodiment are also denoted with thesame reference numerals in the present embodiment, and detaileddescription thereabout is omitted.

In the present embodiment, in the temporary bonding apparatus 20 asshown in FIG. 1, the dispenser 21 dispersedly applies, in spots manner,the temporary bonding agent which is non-reducing organic agent onto thesubstrate surfaces formed with solder such as solder bump.

FIGS. 11( a) and 11(b) illustrate an example of a case where a temporarybonding agent 55 is dispersedly applied in spots manner. FIG. 11( a) isa top view illustrating a substrate 50 a. FIG. 11( b) illustratessubstrates 50 a, 50 b which are temporarily bonded.

In the case as shown in FIGS. 11( a) and 11(b), the temporary bondingagent 55 is applied in spots manner to four corners of a rectangularsubstrate (chip). When the flux is applied, the flux must be applied tothe solder surface so that it comes into contact therewith because it isa primary purpose to reduce and remove the oxide film on the surface ofthe solder with the flux. However, in the present embodiment, the oxidefilm on the surface of a solder 54 is reduced with the carboxylic acidvapor, and therefore, the temporary bonding agent 55 is sufficient aslong as the temporary bonding agent 55 simply gives the retaining force(stack force) between the substrates. Therefore, the temporary bondingagent 55 need not be applied onto the surface of the solder 54 so thatit comes into contact therewith. Therefore, as shown in FIGS. 11( a) and11(b), the temporary bonding agent 55 may be applied to the surface ofthe solder 54 so that it does not come into contact therewith.

The type, temperature condition, vacuum degree condition, carboxylicacid gas, solder bump diameter, pitch size, and the like of thetemporary bonding agent 55 are the same as those of the firstembodiment.

Even when the temporary bonding agent 55 is dispersedly applied in spotsmanner as described above, the flux-free solder bonding can be madewhile suppressing the positional displacement of the substrates 50 a, 50b. Moreover, since the temporary bonding agent 55 is dispersedly appliedin spots manner, the temporary bonding agent 55 can be easilyevaporated. In particular, since the temporary bonding agent 55 can beapplied without coming into contact with the surface of the solder, thetemporary bonding agent 55 does not come into the gaps between theadjacent solder bumps 54, and evaporation and removal can be doneeasily.

Further, if the effect of the temporary bonding can prevent the positionof the solder bump 54 from deviating from the position of the electrodestructure (copper post, barrier layer, solder bump of the othersubstrate, and the like), small positional displacement can beself-aligned with the effect of the surface tension of the solder whenthe solder bump 54 is melted, so that the positional displacement iscorrected. In particular, the effect of self-alignment is high in thepresent embodiment in which the amount of temporary bonding agent 54 issmall.

In the above explanation, the temporary bonding agent 55 is applied inspots manner (dots manner). However, the present embodiment is notlimited to this case, and the temporary bonding agent 55 may be appliedin a linear manner (line manner). Alternatively, instead of dispersedlyapplying the temporary bonding agent 55 to multiple spots, the temporarybonding agent 55 may be applied in a spot manner or a line manner.

According to the present embodiment, not only the effects (1) to (12) ofthe first embodiment but also the following effects can be obtained.

(13) A sufficient amount of retaining force (stack force) can be givento the substrate, and the temporary bonding agent is dispersedly appliedin spots manner, and therefore, the temporary bonding agent can beeasily evaporated.

(14) In particular, when the temporary bonding agent is applied so asnot to be in contact with the surface of the solder, the temporarybonding agent does not enter into the gaps between the solder bumps, andevaporation and removal can be done easily.

Third Embodiment

In the explanation about the above first and second embodiments, thetemporary bonding agent which is the non-flux organic agent, i.e., thenon-reducing organic agent, is applied as the temporary bonding agent 55to the substrates, so that the substrates are temporarily bonded.

It is true that in terms of not causing migration and othercontaminations even when a very small amount of temporary bonding agent55 remains without being completely evaporated, it is desirable to usethe non-reducing organic agent, which is not the flux agent, as thetemporary bonding agent 55, but the present invention is not limited tothis case.

More specifically, according to the present invention, multiple bondedmembers are temporarily bonded with the organic agent interposedtherebetween, and then, before the solder is melted, the organic agentis evaporated, and therefore, even if flux agent is used as the organicagent, it is not necessary to provide a step of removing the flux bycleaning treatment such as solution cleaning and ion etching after thesolder bonding is made. Therefore, for example, even when the pitchinterval between adjacent solder bumps or the diameter of the solderbump 54 is several dozens of μm or less, it is not necessary to considerthe issue of the difficulty of removing the flux. Therefore, accordingto the present invention, even if the flux agent is used, no fluxresidue is generated after the solder bonding is made, and therefore,insulation failure called migration can be prevented from occurring.Finally, in the step of filling the underfill resin 56 into thesubstrates, generation of clearances called voids caused by insufficientfilling of the underfill resin 56 due to the flux residue can beprevented.

As described above, the present invention can be widely applied, as longas multiple substrates are temporarily bonded with the organic agentinterposed therebetween by applying the organic agent to the multiplesubstrates 50 a, 50 b so that the organic agent is sandwiched betweenthe multiple substrates 50 a, 50 b, and the multiple temporarily bondedmembers are heated, and before the solder is melted or while the solderis melted, the organic agent is evaporated, and the solder is melted inthe chamber 31, so that the multiple substrates are bonded with solderwith the solder interposed therebetween.

Fourth Embodiment

Subsequently, the fourth embodiment of the present invention will beexplained.

In the first to third embodiments, the substrate bonding technique hasbeen explained, but the present invention can also be applied to solderforming techniques. More specifically, the present embodiment relates toa heating and melting treatment method for forming solder bumps on asubstrate 50 a which is a member with a solder material 54 b attached.

The solder material 54 b is attached onto the substrate 50 a (member),and the temporary bonding agent 55 which is the organic agent is appliedonto the surface of the substrate 50 a, and the position of the soldermaterial 54 b is temporarily bonded with the temporary bonding agent(organic agent) 55 interposed therebetween. Then, the temporary bondingagent 55 is evaporated before the solder material 54 b is melted orwhile the solder material 54 b is melted. Then, the solder bumps 54 areformed by melting the solder material 54 b. Even in this case,positional displacement of the solder material 54 b is prevented.

For this processing a heating and melting treatment system is provided.This system is the same as the system of FIG. 1. The system is a heatingand melting treatment system for forming solder by performing theheating and melting treatment on the solder material 54 b by heating themember with the solder material 54 b attached. Further, the systemincludes the temporary bonding apparatus 20 for applying the organicagent onto the surface of the member in order to attach the soldermaterial 54 b onto the member and temporarily bonding the soldermaterial 54 b, a heating unit (solder melting apparatus 30) for heatingthe member to which the solder material is temporarily bonded, with thetemporary bonding agent interposed therebetween, and a providing unitfor providing the carboxylic acid vapor to the member, wherein beforethe solder material is melted or while the solder material is melted,the heating unit evaporates the temporary bonding agent, and heats themember in order to form solder without flux in an atmosphere includingthe carboxylic acid vapor.

Except these features, it is the same as the first to third embodiments,and detailed description thereabout is omitted.

EXAMPLE First Example

Substrates 50 a, 50 b having a copper post 52, a barrier layer(Ni/Pd/Au) 53 on the copper post 52, an Sn—Ag solder bump 54 formed onthe bather layer 53 formed on silicon substrates (5 mm square, 25 mmsquare) were prepared. The pair of substrates 50 a, 50 b were prepared.It should be noted that the substrates of which diameter of the solderbump 54 was 100 microns and of which pitch between adjacent solder bumps(distance between centers) was 250 microns were used.

The temporary bonding agent was manufactured by diluting the isobornylcyclohexanol with viscosity modifier (2,4-diethyl-1,5-pentanediol). Atthis occasion, the example is implemented when the ratio of theviscosity modifier was set at 0 weight percent, 30 weight percent, 50weight percent, 70 weight percent, and 90 weight percent. The temporarybonding agent 55 was applied in a planar manner onto the pair ofsubstrates 50 a, 50 b. Then, under the process condition as shown inFIG. 7, the reducing treatment was performed in the formic acidatmosphere, and the flux-less solder bonding was made.

As a result, there was no positional displacement in the substrates 50a, 50 b, and solder bonding was made preferably.

On the other hand, when the treatment was performed in nitrogenatmosphere as the comparative example, there was no positionaldisplacement, but the bonding portion of the solder was not formedpreferably.

Second Example

Substrates of which diameter of the solder bump 54 was 20 microns and ofwhich pitch between adjacent solder bumps (distance between centers) was40 microns were used. The other conditions were the same as those of thefirst example. Even in this case, the positional displacement of thesubstrates 50 a, 50 b was 2 μm or less, and the solder bonding was madepreferably.

Third Example

The same substrates as the first example were temporarily bonded usingthe temporary bonding agent manufactured by diluting the terpineol withthe viscosity modifier (2,4-diethyl-1,5-pentanediol). The example isimplemented when the ratio of the viscosity modifier was set at 0 weightpercent, 30 weight percent, 50 weight percent, 70 weight percent, and 90weight percent. Even in this case, like the first example, thepositional displacement was small, and the solder bonding was madepreferably. However, the yield slightly decreases as compared with thecase of the first example.

Fourth Example

The same substrates as the second example were temporarily bonded usingthe temporary bonding agent manufactured by diluting the terpineol withthe viscosity modifier (2,4-diethyl-1,5-pentanediol). Even in this case,like the second example, the positional displacement was small, and thesolder bonding was made preferably. However, the yield was worse ascompared with the case of the second example.

Fifth Example

The same substrates as the first example were temporarily bonded usingthe temporary bonding agent manufactured by diluting the propyleneglycol phenyl ether with the viscosity modifier(2,4-diethyl-1,5-pentanediol). The example is implemented when the ratioof the viscosity modifier was set at 0 weight percent, 30 weightpercent, 50 weight percent, 70 weight percent, and 90 weight percent.Even in this case, the positional displacement was small, and the solderbonding was made preferably. However, the yield was worse as comparedwith the case of the first and third examples.

Sixth Example

The same substrates as the second example were temporarily bonded usingthe temporary bonding agent manufactured by diluting the propyleneglycol phenyl ether with the viscosity modifier(2,4-diethyl-1,5-pentanediol). Even in this case, like the secondexample, the positional displacement was small, and the solder bondingwas made preferably. However, the yield was worse as compared with thecase of the second and fourth examples.

Seventh Example

The same temporary bonding agent was dispersedly applied in spots manneronto the same substrate as the first example at four locations (fourpoints). At this occasion, with the effect of the temporary bonding bythe temporary bonding agent, the positional displacement was alleviated,and the solder bonding could be made. In this example, an experiment wasconducted with a sample in which a small positional displacement ofabout 20 μm between the substrates 50 a, 50 b was made before the solderbonding was made, but when the effect of the temporary bonding canprevent a large positional displacement, the positional displacement wassolved by the self-alignment with the effect of the surface tension ofthe solder due to the melting of the solder bump 54. Therefore, inpractice, this experiment indicates that, by dispersedly applying thetemporary bonding agent, the positional displacement between themultiple substrates can be alleviated although the cleaning treatmentcan be omitted when the soldering substrate is manufactured by bondingmultiple substrates with each other with solder.

Eighth Example

The same temporary bonding agent was dispersedly applied in spots manneronto the same substrate as the second example at four locations. Even inthis case, the positional displacement between multiple substrates wasalleviated.

Ninth Example

A temporary bonding agent manufactured by diluting the terpineol withthe viscosity modifier (2,4-diethyl-1,5-pentanediol) at 0% to 90 weightpercent was dispersedly applied to four locations in spots manner to thesame substrates as the first example. Likewise, the temporary bondingagent was also dispersedly applied to four locations in spots manner tothe same substrates as the second example. These also alleviated thepositional displacement between the multiple substrates, which was thepractical level.

Tenth Example

A temporary bonding agent manufactured by diluting the propylene glycolphenyl ether with the viscosity modifier (2,4-diethyl-1,5-pentanediol)at 0% to 90 weight percent was dispersedly applied to four locations inspots manner to the same substrates as the first example. Likewise, thetemporary bonding agent was also dispersedly applied to four locationsin spots manner to the same substrates as the second example. These alsoalleviated the positional displacement between the multiple substrates,which was the practical level.

Hereinabove, embodiments suitable for the present invention have beenexplained. The present invention is not limited to the above cases, andaddition, deletion, change, and the like can be made without deviatingfrom the scope of the claims. In the above explanation, the pair ofsemiconductor substrates have been explained as the bonding structures,for example. It is to be understood that the bonded structures to whichthe present invention relates include various kinds of solder-bondedsubstrates, solder-bonded chips (flip-chip-bonded chips and the like),and one obtained by bonding a substrate and a chip. In the aboveexplanation, use of the solder bumps as solder has been mainlyexplained. However, the present invention is not limited to the cases.

This application is based on Japanese Patent Application No. 2010-146337filed on Jun. 28, 2010, and Japanese Patent Application No. 2010-166448filed on Jul. 23, 2010, and the entire contents of the disclosure areincorporated herein by reference.

REFERENCE SIGNS LIST

-   1 bonding structure manufacturing system,-   20 temporary bonding apparatus,-   21 dispenser,-   22 alignment mechanism,-   30 solder melting apparatus,-   31 chamber,-   32 providing unit of carboxylic acid,-   33 heater,-   34 providing system,-   35 valve,-   36 sealed container,-   37 valve,-   38 carrier gas providing tube,-   39 discharge pump,-   40 carboxylic acid collecting unit,-   41 nitrogen providing tube,-   42 valve,-   50 (50 a, 50 b) semiconductor substrate,-   51 semiconductor substrate main body,-   52 copper post (first protruding portion),-   53 barrier layer,-   54 solder bump,-   55 temporary bonding agent,-   56 underfill resin.

1. bonding structure manufacturing method for manufacturing a bondingstructure by bonding a plurality of bonded members with a heat-meltingmaterial interposed therebetween, the bonding structure manufacturingmethod comprising: a step of preparing the bonded members with theheat-melting material being formed on at least one of the plurality ofbonded members; a temporary bonding step for applying a temporarybonding agent onto surfaces of the plurality of bonded members facingeach other, thereby temporarily bonding the plurality of bonded memberswith the temporary bonding agent interposed therebetween; a bonding stepfor melting the heat-melting material without flux by performing heattreatment in an atmosphere including carboxylic acid vapor, therebybonding the plurality of bonded members with the heat-melting materialinterposed therebetween; and an evaporation step for evaporating thetemporary bonding agent by heat application, which is performed beforeor after the bonding step or over the bonding step.
 2. The bondingstructure manufacturing method according to claim 1 for manufacturingthe bonding structure by bonding the plurality of bonded members withthe heat-melting material interposed therebetween, the bonding structuremanufacturing method comprising: a step of preparing the bonded memberswith the heat-melting material formed on at least one of the pluralityof bonded members; a temporary bonding step for applying the temporarybonding agent onto surfaces of the plurality of bonded members facingeach other, thereby temporarily bonding the plurality of bonded memberswith the temporary bonding agent interposed therebetween; an evaporationstep for heating the plurality of bonded members which are temporarilybonded, thereby evaporating the temporary bonding agent before theheat-melting material is melted or while the heat-melting material ismelted; and a bonding step for melting the heat-melting material,thereby bonding the plurality of bonded members with the heat-meltingmaterial interposed therebetween.
 3. The bonding structure manufacturingmethod according to claim 2, wherein the heat-melting material is asolder material or a eutectic-bonding agent, and in the bonding step,the plurality of bonded members are bonded with solder or bonded witheutectic-bonding.
 4. The bonding structure manufacturing methodaccording to claim 2, wherein in the bonding step, an electrodestructure provided on one of the plurality of bonded members iselectrically connected to an electrode structure provided on the otherof the bonded members.
 5. The bonding structure manufacturing methodaccording to claim 2, wherein after all of the temporary bonding agentis evaporated, the heat-melting material is melted in the bonding step.6. The bonding structure manufacturing method according to claim 5,wherein in the temporary bonding step, a temporary bonding agent whichis a non-reducing organic agent is applied as the temporary bondingagent, in the bonding step, heat treatment is performed in an atmosphereincluding carboxylic acid vapor, and the solder bonding or theeutectic-bonding is made without flux.
 7. The bonding structuremanufacturing method according to claim 6 comprising a providing stepfor providing the carboxylic acid vapor into a chamber, wherein thebonding step is performed in the chamber.
 8. The bonding structuremanufacturing method according to claim 5, wherein before the bondingstep, the carboxylic acid vapor is provided, and in the evaporationstep, the temporary bonding agent is evaporated before reducingtreatment of an oxide film of the heat-melting material with thecarboxylic acid vapor or in parallel with the reducing treatment.
 9. Thebonding structure manufacturing method according to claim 6, wherein inthe evaporation step, the temporary bonding agent is evaporated beforethe heat-melting material is melted.
 10. The bonding structuremanufacturing method according to claim 5, wherein after the bondingstep, an underfill resin is filled between the plurality of bondedmembers without performing operation of cleaning and removing thetemporary bonding agent.
 11. The bonding structure manufacturing methodaccording to claim 7, wherein in the evaporation step, a vacuum degreein the chamber is temporarily enhanced so that the temporary bondingagent is easily evaporated.
 12. The bonding structure manufacturingmethod according to claim 6, wherein the temporary bonding agent has aboiling point of 100 degrees Celsius to 350 degrees Celsius at apressure of 1×10² to 1×10⁵ Pa.
 13. The bonding structure manufacturingmethod according to claim 6, wherein the temporary bonding agent is atleast one non-reducing organic agent selected from isobornylcyclohexanol, terpineol, and propylene glycol phenyl ether.
 14. Thebonding structure manufacturing method according to claim 6, wherein thetemporary bonding agent includes a plurality of types of non-reducingorganic agents having different boiling points from each other.
 15. Thebonding structure manufacturing method according to claim 6, wherein thetemporary bonding agent is diluted with a viscosity modifier so that aviscosity thereof becomes 1×10² to 1×10⁵ mPa·s.
 16. The bondingstructure manufacturing method according to claim 6, wherein a solderformed on at least one of the plurality of bonded members is a solderbump having a diameter of 100 μm or less, wherein an pitch intervalbetween adjacent solder bumps is 150 μm or less.
 17. The bondingstructure manufacturing method according to claim 6, wherein in thetemporary bonding step, the temporary bonding agent is applied onto thebonded member in spots manner or line manner.
 18. The bonding structuremanufacturing method according to claim 17, wherein in the temporarybonding step, the temporary bonding agent is dispersedly applied ontothe bonded member at a plurality of location.
 19. The bonding structuremanufacturing method according to claim 17, wherein the temporarybonding agent is applied onto the bonded member in such a manner that itis spaced apart from a surface of the solder.
 20. The bonding structuremanufacturing method according to claim 6, wherein in the temporarybonding step, the temporary bonding agent is applied onto the bondedmember in a planar manner.
 21. The bonding structure manufacturingmethod according to claim 6, wherein the electrode structure provided onone of the plurality of bonded members includes a first electrode layer,a barrier layer formed on the first electrode portion, and a solder bumpformed on the barrier layer, the electrode structure provided on theother of the plurality of bonded members includes a second electrodelayer, and the solder bump and the second electrode layer are bonded bythe solder bonding.
 22. A bonding structure manufacturing system formanufacturing a bonding structure by bonding a plurality of members witha heat-melting material interposed therebetween, the bonding structuremanufacturing system comprising: an application unit for applying atemporary bonding agent, which is a non-reducing organic agent, onto thebonded members with the heat-melting material being formed on at leastone of the plurality of bonded members; a heating unit for heating theplurality of bonded members temporarily bonded while the plurality ofbonded members are stacked with the temporary bonding agent interposedtherebetween; and a providing unit for providing carboxylic acid vaporto the plurality of bonded members, wherein before the heat-meltingmaterial is melted or while the heat-melting material is melted, theheating unit evaporates the temporary bonding agent, and on the otherhand, the heating unit heats the bonded members so as to bond the bondedmembers without flux in an atmosphere including the carboxylic acidvapor.
 23. A heating and melting treatment method for forming a solderby heating a member with a solder material attached and performingheating and melting treatment on the solder material, the heating andmelting treatment method comprising: a temporary bonding step forattaching the solder material onto the member, applying an organic agentonto a surface of the member, and temporarily bonding a position of thesolder material with the organic agent interposed therebetween; anevaporation step for evaporating the organic agent by performing heattreatment in an atmosphere including a carboxylic acid vapor, before aheat-melting material is melted without flux or while the heat-meltingmaterial is melted without flux; and a forming step for forming a solderby melting the heat-melting material.
 24. A heating and meltingtreatment method for forming a solder by heating a member with a soldermaterial attached and performing heating and melting treatment on thesolder material, the heating and melting treatment method comprising: atemporary bonding step for attaching the solder material onto themember, applying an organic agent onto a surface of the member, andtemporarily bonding the solder material with the organic agentinterposed therebetween; an evaporation step for evaporating the organicagent by performing heat treatment in an atmosphere including acarboxylic acid vapor, before the solder material is melted without fluxor while the solder material is melted without flux; and a forming stepfor forming a solder by melting the solder material.
 25. A heating andmelting treatment system for forming a solder by heating a member with asolder material attached and performing heating and melting treatment onthe solder material, the heating and melting treatment systemcomprising: an application unit for applying the solder material ontothe member, and applying an organic agent onto a surface of the memberin order to temporarily bond the solder material; a heating unit forheating the member with the solder material temporarily bonded with thetemporary bonding agent interposed therebetween; and a providing unitfor providing carboxylic acid vapor to the member, wherein before thesolder material is melted or while the solder material is melted, theheating unit evaporates the temporary bonding agent, and on the otherhand, the heating unit heats the member so as to form a solder withoutflux in an atmosphere including the carboxylic acid vapor.